When Cats Don’t Get Along

Pamela J. Reid, Ph.D., ASPCA

Sparky, a three-year-old female domestic shorthair, lived the good life. She was the only companion animal in her household, and her guardian, Louis, treated her like a queen. That is, until the day Louis surprised her with a feline “friend,” a four-month-old domestic shorthair named Sol. Now Sparky had to share her quiet, comfy home with a rambunctious, rowdy teenager. Sol came to his new home from the shelter ready to play with his new companion. But with no say in this new housing decision, resident-cat-turned-roommate Sparky began terrorizing the newcomer. That’s when Louis contacted me for help. She was distraught: She couldn’t bear to give up either cat and desperately needed a solution.

Domestic Violence

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When Louis first brought Sol home, Sparky was able to tolerate him — barely. But as soon as Sol turned six months old and became more playful, Sparky began stalking him around the apartment and preventing him from accessing Louis. She charged him if he tried to go into Louis’s bedroom. She trapped him inside the covered litter box until he began eliminating on the floor. Sparky harassed and attacked Sol so often, in fact, that the little cat spent most of his days and nights hiding in a kitchen cupboard, and the only time the cats could be together was after breakfast, when Sol was sleepy. Then — and only then — would Sparky sit beside him and wash his face. But if he happened to wake up in the middle of the grooming session, she attacked him.

Nervous and timid by nature, Sparky startled and hid under the bedcovers at the slightest noise, even everyday noises like the opening and closing of the elevator door. It was clear to me that Sparky suffered from a combination of defensive and territorial aggression. As Sol grew to adult size and became more playful, he became too intimidating for Sparky to tolerate. That’s why Sparky enjoyed grooming Sol when he was sleepy and lethargic — he posed little threat to her.

Louis had to rearrange her home in order to accommodate both cats. At first, the cats were kept in separate rooms and were encouraged to play “paws” under the doors. Louis also minimized unpleasant interactions between the cats and helped Sparky associate Sol’s presence with good things like treats and toys. The cats were brought together, separated by wire mesh, for their meals. Gradually, Louis let them interact more often, usually after meals when the cats were most likely to be relaxed and content. When they were ready for more direct contact, Louis first tired Sol out with vigorous play so he’d be more subdued for his date with Sparky. She also rubbed tuna juice on their heads to encourage them to groom each other. She introduced kitty condos, with multiple high ledges, so the cats could easily escape from each other, and she added extra litter boxes and removed the covers so Sol couldn’t be trapped during a vulnerable moment.

Making Up Is Hard to Do
Louis saw a decrease in aggression between the cats. Sparky adopted one of the condos as her own, making it possible for Sol to safely move around the apartment. Problems arose only if Sol startled Sparky or if he became overly active. Things seemed to be moving along smoothly. But two months later, the cats began fighting again, so Sparky’s veterinarian prescribed a low dose of diazepam (Valium®) for her. On the medication, Sparky was much calmer and allowed Sol to come near her again. One year later, Louis says the cats have forged a kind of friendship. They often sleep together and groom each other, but they still lead very separate lives. Fights are virtually nonexistent, although the cats still occasionally hiss and spit. And Louis was able to wean Sparky off the Valium after a few months.

Conflict between resident cats can be difficult to resolve. Mature solitary cats can have a tough time adapting to the introduction of a playful young kitten. While the owner’s intent is usually for the cats to become good companions, often the best that can be achieved with cats who fight is peaceful coexistence with little or no interaction. If a situation like this cannot be resolved, I usually recommend re-homing one cat so that the well-being of both animals is ensured. Luckily, Louis was able to keep both of her companion animals, but it took a lot of patience and time.